Fiber optic connectors are used extensively in the telecommunications, data communications, CATV, medical, aerospace, military and sensor markets, to name a few.
These connectors are generally constructed by a threaded or bayonet-style coupling assembly with a metal, ceramic, plastic, glass or combination thereof, ferrule located at one end of the coupling assembly. This ferrule has a precision bored hole running axially through its center to accommodate the optical fiber.
The end of the ferrule that is mated to another connector is generally factory polished to very tight standards for surface end face finish, geometry, etc, or it is field polished, which yields surface geometries far less exact than obtainable by factory polishing.
One attempt to overcome field polishing is U.S. Pat. No. 5,363,461 to Bergmann which discloses a connector having a short factory polished stub that terminates within the connector. The optical fiber of the cable is inserted through the rear of the connector and mated with the stub fiber. The optical fiber is then glued in place. The problem with the connector in Bergmann is that the fiber optic cable must be glued, thereby creating a permanent installation.
Another attempt to improve the field of connectors is U.S. Pat. No. 5,040,867 to DeJong which provide a connector having a rear crimp tube and crimp ring. The unprotected optical fiber is inserted into the rear crimp tube for coupling with a connector stub fiber. The rear crimp tube is then crimped onto the unprotected optical fiber for a permanent installation. This crimping can easily damage the optical fiber.
One attempt to create a connector which allows for quick connect/disconnect of the fiber optic cable to the connector is U.S. Pat. No. 6,379,052 which uses a spring loaded splice plate within the connector to allow quick insertion, mating and then removal of a fiber optic cable to the connector. This connector has many parts and is expensive to produce. Further, the splice becomes unreliable and harder to maintain as the spring deforms over time. Finally, the splice plate damages bare fibers during repeated insertions and removals.
Although factory and field installation of fiber optic connectors, and the techniques for doing so, have advanced over the years, the techniques vary from connector type to connector type and from connector manufacturer to connector manufacturer. This becomes confusing for installers as they can be faced with the installation of a variety of connectors, which necessitates significant expenditures for installation tools, training, etc. for each of these different connectors.